function bar () {
  var myName = '极客世界';
  let test1 = 100;
  if (1) {
    let myName = "Chrome 浏览器";
    console.log(test);
  }
}
function foo() {
  var myName = '极客邦';
  let test = 2;
  {
    let test = 3;
    bar();
  }
}
var myName = '极客时间';
let myAge = 10;
let test = 1;
foo();